Self servo writing disk controller and methods for use therewith

Abstract

A self servo writing disk controller detects a plurality of spiral sync marks and a plurality of spiral bursts corresponding to one of a plurality of servo spirals from a read signal from the read/write head. A timing reference signal is generated based on timing of at least one of the plurality of the spiral sync marks. A position error signal is generated based on timing of at least one of the plurality of spiral sync marks and a magnitude of at least one of a plurality of spiral bursts. The timing reference signal and the position error signal are used by the disk drive for timing and positioning in self writing initial servo wedges to the disk.

1. A disk controller for use in a self servo writing disk drive having at least one read/write head for writing servo data to a disk in a servo write mode and for reading and writing user data in a user mode, the disk controller comprising:
 a spiral detection module that analyzes a read signal from the read/write head, detects a plurality of spiral sync marks and a plurality of spiral bursts corresponding to one of a plurality of servo spirals written on the disk, and that generates a timing reference signal based on timing of at least one of the plurality of the spiral sync marks and a position error signal based on timing of at least one of the plurality of spiral sync marks and a magnitude of at least one of the plurality of spiral bursts, wherein the spiral detection module compares a magnitude of the read signal to a signal threshold, and wherein spiral detection module triggers the detection of the plurality of spiral sync marks and a plurality of spiral bursts when the magnitude of the read signal compares favorably to the signal threshold and a decoded binary pattern matches a predefined pattern; 
 a timing generator, operably coupled to the spiral detection module, for generating a clock signal and for generating at least one media event trigger that is based on the timing reference signal; 
 a device controller, operably coupled to the spiral detection module, for controlling at least one drive device based on the position error signal; 
 a servo data generation module that generates the servo data corresponding to a plurality of servo wedges of the disk; and 
 a servo write module, operably coupled to the servo data generation module and the timing generator, that generates write signals for writing the plurality of servo wedges on the disk based on the clock signal and the at least one media event trigger. 
 
     
     
       2. The disk controller of  claim 1  wherein the spiral detection module detects the plurality of spiral sync marks based on the detection of peaks in the read signal. 
     
     
       3. The disk controller of  claim 1  wherein the spiral detection module upsamples the read signal to form interpolated read samples and that detects the plurality of spiral sync marks based on the detection of peaks in the interpolated read samples. 
     
     
       4. The disk controller of  claim 1  wherein the spiral detection module detects the plurality of spiral sync marks by detecting a first of the plurality of spiral sync marks, generating a spiral sync mark timing window that corresponds to the estimated timing of a subsequent one of the plurality of spiral sync marks, and the detection of the subsequent one of the plurality of spiral sync marks within the spiral sync mark timing window. 
     
     
       5. The disk controller of  claim 1  wherein the spiral detection module detects the plurality of spiral bursts by detecting one of the plurality of spiral sync marks, generating a spiral burst timing window that corresponds to the estimated timing of a subsequent spiral burst of the plurality of spiral bursts, and the detection of the subsequent one of the plurality of spiral bursts within the spiral burst timing window. 
     
     
       6. The disk controller of  claim 1  wherein the spiral detection module identifies a centermost one of the plurality of spiral sync marks and that generates the position error signal based on a magnitude of a first of the plurality of spiral burst that precedes the centermost one of the plurality of spiral sync marks and a magnitude of a second of the plurality of spiral burst that succeeds the centermost one of the plurality of spiral sync marks. 
     
     
       7. The disk controller of  claim 6  wherein the spiral detection module integrates the magnitude of the first of the plurality of spiral burst to generate a first integrated burst magnitude and integrates the magnitude of the second of the plurality of spiral bursts to generate a second integrated burst magnitude and that generates the position error signal based on the difference between the first integrated burst magnitude and the second integrated burst magnitude. 
     
     
       8. The disk controller of  claim 1  wherein the spiral detection module integrates a magnitude of the plurality spiral bursts to form a burst magnitude integration, identifies a spiral burst centroid based on the burst magnitude integration, and that generates the position error signal based on a position of the spiral burst centroid. 
     
     
       9. The disk controller of  claim 1  wherein the spiral detection module identifies a centermost one of the plurality of spiral sync marks and generates a timing reference signal based on timing of the centermost one of the plurality of spiral sync marks. 
     
     
       10. A method for use in a disk drive having at least one read/write head for writing servo data to a disk in a servo write mode and for reading and writing user data in a user mode, the method comprising:
 detecting a plurality of spiral sync marks and a plurality of spiral bursts corresponding to one of a plurality of servo spirals from a read signal from the read/write head, wherein the step of detecting a plurality of spiral sync marks and a plurality of spiral bursts includes:
 comparing a magnitude of the read signal to a signal threshold; and 
 triggering the detection of the plurality of spiral sync marks and a plurality of spiral bursts when the magnitude of the read signal compares favorably to the signal threshold; 
 
 generating a timing reference signal based on timing of at least one of the plurality of the spiral sync marks; 
 generating a position error signal based on timing of at least one of the plurality of spiral sync marks and a magnitude of at least one of the plurality of spiral bursts; 
 wherein the timing reference signal and the position error signal are used by the disk drive for timing and positioning in self writing initial servo wedges to the disk. 
 
     
     
       11. The method of  claim 10  wherein the step of detecting a plurality of spiral sync marks and a plurality of spiral bursts includes:
 upsampling the read signal to form interpolated read samples; and 
 detecting the plurality of spiral sync marks based on the detection of peaks in the interpolated read samples. 
 
     
     
       12. The method of  claim 10  wherein the step of generating a timing reference signal includes:
 identifying a centermost one of the plurality of spiral sync marks; and 
 generating a timing reference signal based on timing of the centermost one of the plurality of spiral sync marks. 
 
     
     
       13. The method of  claim 10  wherein the step of detecting a plurality of spiral sync marks and a plurality of spiral bursts includes:
 identifying a centermost one of the plurality of spiral sync marks; 
 wherein the step of generating the position error signal generates the position error signal based on a magnitude of a first of the plurality of spiral burst that precedes the centermost one of the plurality of spiral sync marks and a magnitude of a second of the plurality of spiral burst that succeeds the centermost one of the plurality of spiral sync marks. 
 
     
     
       14. The method of  claim 13  wherein the step of detecting a plurality of spiral sync marks and a plurality of spiral bursts includes:
 integrating the magnitude of the first of the plurality of spiral burst to generate a first integrated burst magnitude; and 
 integrating the magnitude of the second of the plurality of spiral bursts to generate a second integrated burst magnitude; 
 wherein the step of generating the position error signal generates the position error signal based on the difference between the first integrated burst magnitude and the second integrated burst magnitude.